This type of rear projection television is easier to make larger compared to televisions utilizing a Braun tube because its screen can be formed wide with a reduced depth. A rear projection television 1 shown in FIG. 1 has a configuration wherein wood plate materials are used; the plate materials are formed into a box which constitutes a main body portion 2; a screen mounting portion 4 having a screen 3 mounted thereon is mounted on a front side of the main body portion; a mirror mounting portion 6 having a mirror 5 is mounted on a rear side; and a bottom cabinet 7 having video devices and electronic components and the like for projecting images are integrally provided on the lower part of the main body portion 2.
A rear projection television 1 shown in FIG. 2 has a configuration wherein a metal frame 8 in a predetermined shape is placed to erect on a bottom cabinet 7; and a screen mounting portion 4 having a screen 3 and a mirror mounting portion 6 having a mirror 5 are integrally mounted so that they envelope the frame 8 from before and behind it.
In the first example, the screen mounting portion 4 and the mirror mounting portion 6 are mounted on the main body portion 2 which is made of wood in front of and behind it, respectively. The size of the main body portion 2 and the overall size of the television including the mirror mounting portion 6 are determined by the size of a screen, and each part of the housing is formed with a size and dimensional accuracy originally designed to provide a single housing that depends on the size of the television screen, i.e., the size thereof in inches. As a result, such parts are not compatible with other sizes in inches. This results in a problem not only in that production efficiency is low but also in that a need for maintaining predetermined strength of the main body portion 2 of the wood cabinet inevitably increases the thickness of the plates and the overall weight.
In the second example, although the metal frame 8 is used, it is designed as a housing of one size in accordance with the size of a television screen. As a result, there is no compatibility with other sizes in inches at all. At the same time, the use of the metal frame 8 results in a problem not only in that the overall weight is increased but also in that the associated increase in the number of parts makes parts management operations complicated and reduces the efficiency of assembly operations.
Further, in either of the examples, since the housing is formed as a single element, the screen and mirror are mounted in the same space in the housing where other constituent members are provided. This puts them into contact with the air flowing through the interior of the housing. As a result, the screen and mirror get dirty because of dust and the like sticking thereto, which leads to a problem in that the display of images is degraded.
Thus, housings are manufactured to meet each size in inches of television screens, problems to be solved exist in order to simplify the configuration as a whole, to improve compatibility between various sizes in inches, i.e., to achieve ease of manufacture with optical accuracy maintained, and to prevent images from being degraded by dirty optical components.